To pursue high density mounting in semiconductor devices, bare chip mounting is the ideal. However, quality control and handling of bare chips are difficult. For this reason, CSP (chip size/scale package) technology, in which the package size is close to the chip size, has been developed.
In such a CSP semiconductor device, an important problem is to relieve the thermal stress due to the differences in coefficient of thermal expansion between the semiconductor chip and the mounting board. In particular, as the number of pins continues to increase, it is essential that no wiring breaks are caused by thermal stress, since wiring is required to connect from the electrodes to the solder balls.
The present invention addresses the above described problems, and has as its object the provision of an electronic component, a semiconductor device, methods of manufacturing theses a circuit board on which these are mounted, and an electronic instrument having this circuit board.